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Show Figure 2: Exploded View of RO-II Burner Assembly 3. Separate flow control dampers for both the pilot and main air streams. 4. Integral instrumentation which permits burner operators to balance combustion air flow to multiple burner arrays located within a common windbox. 5. Unique helical flow vane assembly which enhances combustion air swirl and improves air distribution within the register. 6. A shadow vane assembly which enhances combustion air swirl but more importantly protects the flow vane assembly and fuel nozzle from damage due to flame radiation in multiple burner installations. Photo 1, an end-on view of the RO-II register assembly, highlights the involute (spirally shaped) air plenum, for both the pilot and main combustion air streams, and the shadow vane assembly. Photo 2 highlights the flow vane assembly utilized in the RO-II register. The helical vane arrangement is shown separate from the air register. Note that the pilot combustion air stream passes through six (6) vanes at the rear of the burner Photo 1 End-on View of the RO-II Register Assembly 2 Photo 2: Helical Flow Vane Assembly (i .e. the widest part of the vane assembly), the main combustion air stream passes through eight (8) vanes near the burner front (i .e. the narrowest part of the vane assembly). It should also be noted that the register design requires minimal maintenance since the only moving parts are the pilot and main air dampers. These same dampers also provide the register with the ability to compensate for burner to burner combustion air flow imbalances in multiple burner/common windbox arrangements. The RO-II development program was largely comprised of extensive combustion trials of potential RO-II firing system hardware. These trials were conducted in one of ASS-CE's front wall-fired large scale laboratory test furnaces. ASS-CE's development philosophy was to conduct tests with hardware designed to operate at a heat input rate of 50 x 106 Stu/hr. This rate is identical to the design heat input rate of the burners to be installed in two units in Jamestown, NY. Sy adopting this development philosophy, ASS-CE could confidently accelerate the process of transitioning laboratory hardware developments into commercial application. Prior to conducting the laboratory combustion trials, ASS-CE evaluated the air register's near-field aerodynamics. The objective of these tests was to define key aerodynamic characteristics of the register in order to support the design of compatible coal nozzle configurations. Recirculation zone size and strength as well as the air reg ister's potential to control stoichiometry in the burner near field (through internal air staging) were assessed. These aerodynamic properties were consistent with the low NOx objectives of the RO-II development program. Laboratory combustion trials began following the register aerodynamic study. The focus of these trials was to evaluate the combustion performance of a variety of air register/coal nozzle configurations. The performance of each configuration was evaluated in comparison with th~ overall performance targets for the RO-II burner. It should be noted that the air register configuration remained fixed throughout the trials. Development activities concentrated on combining advanced low NOx |